Peter Huttenlocher has left the building

The New York Times has an obituary for child neurologist Peter Huttenlocher, who surprised everyone by finding that the human brain loses connections as part of growing into adulthood.

Huttenlocher counted synapses – the connections between neurons – and as a paediatric neurologist was particularly interested in how the number of synapses changed as we grow from children to adults.

Before Huttenlocher’s work we tended to think that our brain’s just got more connected as we got older, but what he showed was that we hit peak connectivity in the first year of life and much of brain development is actually removing the unneeded connections.

This is know as synpatic pruning and it was demonstrated with this graph from classic 1990 paper.

I love this graph for a couple of reasons. Firstly, it’s a bit wonky. It was hand-drawn and whenever it is reproduced, as it has been in many textbooks, it’s always a bit off-centre.

Secondly, it’s crystal clear. It’s a graph showing the density of synaptic connections in the visual cortex of the human brain and you can see it’s rapidly downhill from the first year of life until the late teens where things start to even out.

This is a good thing as the infant brain starts over-connected but loses anything that isn’t needed as we learn which skills are most important, and we are left with only the most efficient neural connections, through the experience of growing up.

One of Huttenlocher’s discoveries was that this process of synaptic pruning may go wrong in people who have neurodevelopmental disorders.

Link to NYT obituary for Peter Huttenlocher.

Are classical music competitions judged on looks?

Looking at the evidence behind a recent news story

The headlines

The Los Angeles Times: People trust eyes – not ears – when judging musicians

Classic FM: Classical singers judged by actions not voice

Nature: Musicians’ appearances matter more than their sound

The story

If you wanted to pick out the musician who won a prestigious classical music competition would you listen to a clip of them playing or watch a silent video of them performing the same piece of music?

Most of us would go for an audio clip rather than video, and we’d be wrong. In a series of experiments, Chia-Jung Tsay from University College London, showed that both novices and expert musicians were better able to pick out the winners when they watched rather than listened to them.

The moral, we’re told, is that how you look is more important than how you sound, even in elite classical music competitions.

What they actually did

Dr Tsay, herself a classically trained musician, used footage from real international classical music competitions. She took the top three finalists and asked volunteers to pick out the real winner – with a cash incentive – by looking at video without sound, sound without video, or both.

Over a series of experiments she showed that people think that audio will be more informative than video, but actually people are able to pick the real winner when watching video clips. But they aren’t able to do this when listening to audio clips (these test subjects only perform at the level of chance). The shocking thing is that when people get sound and video clips, which notionally contain more information, they still perform at chance. The implication being that they would do better if they could block their ears and ignore the sound.

Follow up experiments suggested that people’s ability to pick winners depended on their being able to pick out things associated with “stage presence”. A video reduced to line drawings, designed to remove details and emphasise motion, still allowed people to pick out winners at an above chance rate. Another experiment showed that asking people to identify the “most confident, creative, involved, motivated, passionate, and unique performer” tallied with the real winners.

How plausible is this?

We’re a visual species. How things look really matters, as everyone who has dressed up for an interview knows. It’s also not uncommon for us to be misled into believing that how something looks isn’t as important as it really is (here’s an example: judging wine by the labels rather than the taste).

What is less plausible is the spin put on the story by the headlines. We all know that looks are important, but how can they really be more important than sound in a classical music competition? The most important thing really is the sound, but this research resonates with a popular cliché about how irrational we are.

Tom’s take

The secret to why these experiments give the results they do is in this detail: the judgement that people were asked to make was between the top three finalists in prestigious international competitions. In other words, each of these musicians is among the best in the world at what they do. The best of the best even.

In all probability there is a minute difference between their performances on any scale of quality. The paper itself admits that the judges themselves often disagree about who the winner is in these competitions.

The experimental participants were not scored according to some abstract ability to measure playing quality, but according to how well they were able to match real-world competition outcome.

The experiments show that matching the judges in these competitions can be done based on sight but not on sound. This isn’t because sight reveals playing quality, but because sight gives the experimental participants similar biases to the real judges. The real expert judges are biased by how the performers look – and why not, since there is probably so little to choose between them in terms of how they sound?

This is why the conclusion, spelt out in the original paper, is profoundly misleading: “The findings demonstrate that people actually depend primarily on visual information when making judgements about music performance”. It remains completely plausible that most of us, most of the time, judge music on how it sounds, just like we assumed before this research came out.

In ambiguous cases we might rely on looks over sounds – even the experts among us. This is a blow to musicians who thought it was always just about sound – but isn’t a revelation to the rest of us who knew that when choices are hard, whether during the job interview or the music competition, looks matter.

Read more

The original paper: Sight over sound in the judgment of music performance. Tsay, C-J (2013), Proceedings of the National Academy of Sciences

Special mention for the BBC and reporter Melissa Hogenboom who were the only people, as far as I know, who managed to report this story with an accurate headline: Sight dominates sound in music competition judging

The interaction between the senses is an active and fascinating research area. Read more from the Crossmodal Research Laboratory at the Univeristy of Oxford and Cross-modal perception of music network at the University of Sheffield

The Conversation

This article was originally published at The Conversation.
Read the original article.

A detangler for the net

I’ve just finished reading the new book Untangling the Web by social psychologist Aleks Krotoski. It turns out to be one of the best discussions I’ve yet read on how the fabric of society is meshing with the internet.

Regular readers know I’ve been a massive fan of the Digital Human, the BBC Radio 4 series that Krotoski writes and presents, that covers similar territory.

Untangling the Web takes a slightly more analytical angle, focusing more on scientific studies of online social interaction and theories of online psychology, but it is all the richer for it.

It covers almost the entire range psychological debates: friendships, how kids are using the net, debates over whether the net can ‘damage the brain’, online remembrance and mourning, propaganda and persuasion, sex, dating and politics. You get the idea. It’s impressively comprehensive.

It’s not an academic book but, unsurprisingly, given Krotoski’s background as both a social psychologist and a tech journalist, is very well informed.

I picked up a couple of minor errors. It suggests internet addiction was recognised as a diagnosis in the DSM-IV, when the nearest things to an internet addiction diagnosis was only discussed (and eventually relegated to the Appendix), in the DSM-5.

It also mentions me briefly, in the discussion of public anxieties that the internet could ‘rewire the brain,’ but suggests I’m based at University College London (apparently a college to the north of the River Thames) when really I’m from King’s College London.

But that was about the best I could do when trying to find fault with the book. It’s a hugely enjoyable, balanced treatment of an often inflammatory subject, that may well be one of the best guides to how we relate over the net that you’re likely to read for a long time.

Link to more details about Untangling the Web.

Super-recogniser officers policing Europe’s biggest party

The Guardian are reporting that the London Metropolitan Police have deployed ‘super recogniser’ officers to Notting Hill Carnival to pick out known criminals from the crowd.

This is curious because this is a verified ability that has only recently been reported in the scientific literature.

It has been long known that some people have severe difficulties recognising faces – something called prosopagnosia and sometimes inaccurately labelled ‘face blindness’.

But more recently, it was discovered that a tiny minority of people are ‘super recognisers’ – with exceptional face recognition abilities – meaning they can pick out a previously identified face from huge numbers of possibilities.

A more recent fMRI study found that super recognisers tend to show a greater level of activity in the fusiform gyrus.

This area is heavily associated with face recognition, although debates are ongoing whether it is face-dedicated or just specialised for learned fine-grained visual recognition of various sorts.

It’s not clear how the Met Police identified their ‘super recogniser’ officers but it seems it might be an interesting exercise in screening for key neuropsychological characteristics and deploying those officers to the appropriate task.

Needless to say, picking out a few dodgy faces from a street party that welcomes a million people every year would be exactly this sort of job.

More details from the The Guardian report:

…17 specialist officers will be holed up in a central control room several miles away in Earls Court monitoring live footage in an attempt to identify known offenders.

Chief superintendent Mick Johnson from the Metropolitan police said it was the first time the “recognisers” – who have been selected for their ability to remember hundreds of offenders’ faces – have been used to monitor a live event.

“This type of proactive operation is the first one we have done in earnest in real time so we are going to be looking at it very closely to see how effective it is and what we get out of it,” he said.

The Met has 180 so-called super recognisers – most of whom came to the fore in the aftermath of the London riots when they managed to identify more than a quarter of the suspects who were caught on CCTV footage…

One of the super recognisers on duty will be Patrick O’Riordan, who says he has had an ability to pick people out in a crowd and recall faces since he joined the Met 11 years ago.

“It is with me all the time. Often when I am on a day off or out with my girlfriend I will see someone and know straight away who they are and where they fit in,” said 45-year-old. “It could be their eyes or the shape of their forehead or their gait, but something usually sticks with me. It something that started from day one as a police officer – really it is just something that I took too naturally.”

Link to Guardian article on super recogniser officers at the Carnival.
Link to summary of study that identified ‘super recognisers’.
pdf of full-text of the same paper.

Period architecture, majestic views, history of madness

Regular readers will know of my ongoing fascination with the fate of the old psychiatric asylums and how they’re often turned into luxury apartments with not a whisper of their previous life.

It turns out, a 2003 article in The Psychiatrist looked at exactly this in 71 former asylum care hospitals.

It’s cheekily called ‘The Executives Have Taken Over the Asylum’ and notes how almost all have been turned into luxury developments. Have a look at Table 1 for a summary.

The authors also had a look at the marketing material for these new developments and wrote a cutting commentary on how the glossy brochures deal with the institutions’ mixed legacies.

The estate agents want to play on the often genuinely beautiful architecture and, more oddly, the security of the sites, while papering over the fact the buildings had anything to do with mental illness.

Examples of the language employed by property developers in sales brochures advertising old hospital buildings included ‘sanctuary’ and ‘seclusion’ in ‘grade II listed buildings’, ‘tastefully converted period buildings’ and ‘luxury penthouses’. There was a strong emphasis on security, with ‘a secure and private environment’, ‘24 hour security guards’, ‘security gates’ and ‘CCTV surveillance’. Original asylum architecture is even imitated in modern buildings: ‘the classic facades that emulate the original architecture’, and the clock tower of one former hospital was used as a symbol to represent the whole development.

Residents at the redeveloped site of Nethern Hospital will be greeted by ‘the gentle bounce of tennis balls on private courts’ and ‘the distant voices of children’. They will, however, remain unaware of the 1976 inquiry into high levels of suicides that found serious understaffing and unsatisfactory conditions on the wards.

At St George’s Park in Oxfordshire [previously Littlemore Hospital], prospective buyers were informed of the ‘original 19th century elegance’ and ‘original features including high ceilings’. They are not informed that the original psychiatric hospital has been newly built over the road.

In total, reference was made to the former psychiatric hospitals in only four of the 12 promotional brochures and web sites. This was in the general reference to a former hospital or by euphemistic language, such as ‘society’s less able’, referring to people with learning disability at Earlswood Hospital.

Since the article was written in 2003, many more have gone the same way.

Link to ‘The Executives Have Taken Over the Asylum’.

A technoculture of psychosis

Aeon Magazine has an amazing article on the history of technology in paranoid delusions and how cultural developments are starting to mirror the accidental inventions of psychosis.

It’s by the fantastic Mike Jay, who wrote The Air Loom Gang, an essential book that looks at one of the most famous cases of ‘influencing machine’ psychosis.

In his article, Jay applies the same keen eye for history and culture and explores how the delusions of psychosis are carefully intertwined with culture.

Persecutory delusions, for example, can be found throughout history and across cultures; but within this category a desert nomad is more likely to believe that he is being buried alive in sand by a djinn, and an urban American that he has been implanted with a microchip and is being monitored by the CIA. ‘For an illness that is often characterised as a break with reality,’ they observe, ‘psychosis keeps remarkably up to date.’ Rather than being estranged from the culture around them, psychotic subjects can be seen as consumed by it: unable to establish the boundaries of the self, they are at the mercy of their often heightened sensitivity to social threats.

The article covers everything from Victorian delusions of electrical control, to the breakdown of novelist Evelyn Waugh, to the fiction of Philip K Dick.

It’s an excellent piece, and even those who have a special interest in the history of psychosis will find it full of fascinating gems.

By the way, it looks like Jay’s book The Air Loom Gang is about to be re-released in a newly updated version, under a new title The Influencing Machine.

Link to ‘The Reality Show’ in Aeon Magazine.

The deafening silence

All silences are not equal, some seem quieter than others. Why? It’s all to do with the way our brains adapt to the world around us, as Tom Stafford explains

A “deafening silence” is a striking absence of noise, so profound that it seems to have its own quality. Objectively it is impossible for one silence to be any different from another. But the way we use the phrase hints at a psychological truth.

The secret to a deafening silence is the period of intense noise that comes immediately before it. When this ends, the lack of sound appears quieter than silence. This sensation, as your mind tries to figure out what your ears are reporting, is what leads us to call a silence deafening.

What is happening here is a result of a process called adaptation. It describes the moving baseline against which new stimuli are judged. The way the brain works is that any constant simulation is tuned out, allowing perception to focus on changes against this background, rather than absolute levels of stimulation. Turn your stereo up from four to five and it sounds louder, but as your memory of making the change rapidly fades, your mind adjusts and volume five becomes the new normal.

Adaptation doesn’t just happen for hearing. The brain networks that process all other forms of sensory information also pull the same trick. Why can’t you see the stars during the daytime? They are still there, right? You can’t see them because your visual system has adapted to the light levels from the sun, making the tiny variation in light that a star makes against the background of deep space invisible. Only after dark does your visual system adapt to a baseline at which the light difference created by a star is meaningful.

Just as adaption applies across different senses, so too does the after-effect, the phenomenon that follows it. Once the constant stimulation your brain has adapted to stops, there is a short period when new stimuli appear distorted in the opposite way from the stimulus you’ve just been experiencing. A favourite example is the waterfall illusion. If you stare at a waterfall (here’s one) for half a minute and then look away, stationary objects will appear to flow upwards. You can even pause a video and experience the illusion of the waterfall going into reverse.

It’s a phenomenon called the motion after effect. You can get them for colour perception or for just lightness-darkness (which is why you sometimes see dark spots after you’ve looked at the sun or a camera flash).

After-effects also apply to hearing, which explains why a truly deafening silence comes immediately after the brain has become adapted to a high baseline of noise. We perceive this lack of sound as quieter than other silences for the same reason that the waterfall appears to suck itself upwards.

So while it is true that all silences are physically the same, perhaps Spinal Tap lead guitarist Nigel Tufnel was onto something with his amplifier dials that go up to 11. When it comes to the way we perceive volume, it is sometimes possible to drop below zero.

This was my BBC Future from last weekend. The original is here.